I'm not a "DRG"(Deep Rock Galactic) developer, so I don't know if it's true or not, but I can tell you about "Marching cubes."

"Marching cubes" can also be used in "Voxel", but "Matching cubes" can be used without "Voxel". Therefore, the cave surface of "DRG" is not "Voxel", but "DRG" may have used "Matching cubes".

"Voxel" is calculated based on particles of all volumes in space. However, "DRG" may not be computed as the particles that make up the cave wall.

For example, if the player is looking at the inner surface of the sphere in the empty space of the sphere, "Voxel" records and manages particles in all worlds except the empty space of the sphere.(Every time a player moves, it will be saved, recorded, and loaded on the computer according to the unit size of the world set.) However, the estimated method of "DRG" records only a empty sphere, and the computer manages only one empty sphere.

In another example, Minecraft, such as the game of "Voxel", is calculated in units of "Chunk". That is, 32,256 filled blocks(16x16x126) are recorded. If we break one of them, the value of one of the 32,256 recorded changes. Conversely, the estimated method of "DRG" is calculated in units of empty spaces regardless of the shape of the empty spaces. so, The more complex and larger the cave is, the more units such as "(Minecraft's)Chunk" are to be calculated. In other words, it can be estimated that the more the player picks, the more empty space the computer calculates.

These two methods have something in common with the use of "Marching cubes" in the description of the terrain, and the generation of the world itself is different.

Therefore, if "DRG" is not "Voxel", or if "DRG" developers said not "Voxel", the world generation appears to have been "Marching cubes" as a unit of blank space.